1. (

• killer ,
• slayer

) someone who causes the death of a person or animal ;

2. (

• cause_of_death ,
• killer

) the causal agent resulting in death; "heart disease is the biggest killer in the United States" ;

3. (

• killer

) a difficulty that is hard to deal with; "that exam was a real killer" ;

4. (

• killer_whale ,
• killer ,
• orca ,
• grampus ,
• sea_wolf ,
• Orcinus_orca

) predatory black-and-white toothed whale with large dorsal fin; common in cold seas ;